I've played with them a bit but really don't make any money on them between ebay's fees and PP fees you are lucky to break even.
You pretty much only get people who want to get quick feedback so they go looking for the cheep eBooks.
The market is flooded and alot of sellers are giving them away for pennies.
You also risk the chance of negative feedback from the ones who don't read the auction and think you are sending them a real book.
And then there are those who email system stinks and your mail never gets there (mostly AO-hell) resulting once again in negative feedback.
I know some are successful with them but for me it wasn't worth the trouble for my time!
When I had my ebay stores I offered them as add on's and that worked somewhat but as far as the auctions, nope - it was a waste of time
